Spotted this one in B&Q Hedge End where they had 20+ on display. Asked staff if it was nationwide and was decisively told 'probably'. So apologies if it isn't.
Checked prices online, couldn't find the twin pack, but individually the PBH 2000 sells for £67 - £99 (Amazon & Argos respectively), and the PSR 14.4 sells for £49 - £89 (again Amazon & Argos respectively).
Bought individually (but together if you will) from the B&Q website they cost £200!
Hope it helps someone.
edit: thanks for the voucher tip - missed that one! http://www.hotukdeals.com/item/574647/printable-voucher-for-15-off-on-all
Must be used by Tuesday 12th Jan!